Faulty floodgates along the Fraser River are having harmful effects on salmon stocks, according to a new SFU study.

"What we've found is a problem," said study co-author Jonathan Moore. "Many of these floodgates just don't open ... and in those locations there were fewer native fish and the water quality was poor.

Floodgates are small dams located along tributaries which close in order to protect fields and homes in the area, when water levels rise.

The SFU study concludes that many Fraser River floodgates are not functioning properly and preventing juvenile salmon from accessing habitat that's important to their survival. (Jonathan Moore)

However, when flooding isn't an issue, floodgates are supposed to remain open to allow fish and water to pass through.

For the study, co-author Rebecca Seifert installed time-lapse cameras at 20 different lower Fraser River floodgates. Images captured over a six month period showed whether the gates were, in fact, functioning.

"One of the major concerns is that it decreases the amount of nursery habitat that young salmon use —there's less habitat for them to grow up in before they get to the ocean," said Moore.

According the study, habitat around the few floodgates that did work properly wasn't negatively impacted.

A juvenile chinook salmon captured in a trap behind a Fraser River floodgate. Chinooks are one of the main species of concern. (Watershed Watch Salmon Society)

"To us, that really points to a solution of retrofitting or improving operation of floodgates so they are fish friendly," said Moore. "It feels like a potential game changer for salmon habitat in the lower Fraser."